scholarly journals Study of nuclear properties with muonic atoms

2020 ◽  
Vol 135 (10) ◽  
Author(s):  
A. Knecht ◽  
A. Skawran ◽  
S. M. Vogiatzi
Keyword(s):  
Nuclear Charge Radius ◽  
X Rays ◽  
Gas Cell ◽  
Capture Process ◽  
Muonic Atoms ◽  
Hydrogen Deuterium ◽  
Almost All ◽  
Deuterium Gas ◽  
Radioactive Atoms ◽  
Pressure Hydrogen

AbstractMuons are a fascinating probe to study nuclear properties. Muonic atoms can easily be formed by stopping negative muons inside a material. The muon is subsequently captured by the nucleus and, due to its much higher mass compared to the electron, orbits the nucleus at very small distances. During this atomic capture process, the muon emits characteristic X-rays during its cascade down to the ground state. The energies of these X-rays reveal the muonic energy level scheme, from which properties like the nuclear charge radius or its quadrupole moment can be extracted. While almost all stable elements have been examined using muons, probing highly radioactive atoms has so far not been possible. The muX experiment has developed a technique based on transfer reaction inside a high-pressure hydrogen/deuterium gas cell to examine targets available only in microgram quantities.

scholarly journals Massive star mass-loss revealed by X-ray observations of young supernovae

2018 ◽  
Vol 14 (S346) ◽  
pp. 83-87
Author(s):  
Vikram V. Dwarkadas
Keyword(s):  
Mass Loss ◽  
Massive Stars ◽  
Ambient Medium ◽  
Mass Loss Rate ◽  
Stellar Mass ◽  
X Rays ◽  
X Ray ◽  
The Common ◽  
Almost All ◽  
Loss Rates

AbstractMassive stars lose a considerable amount of mass during their lifetime. When the star explodes as a supernova (SN), the resulting shock wave expands in the medium created by the stellar mass-loss. Thermal X-ray emission from the SN depends on the square of the density of the ambient medium, which in turn depends on the mass-loss rate (and velocity) of the progenitor wind. The emission can therefore be used to probe the stellar mass-loss in the decades or centuries before the star’s death.We have aggregated together data available in the literature, or analysed by us, to compute the X-ray lightcurves of almost all young supernovae detectable in X-rays. We use this database to explore the mass-loss rates of massive stars that collapse to form supernovae. Mass-loss rates are lowest for the common Type IIP supernovae, but increase by several orders of magnitude for the highest luminosity X-ray SNe.

X-Ray Absorption Spectroscopy Applied to Metal Accumulation

2009 ◽  
Vol 71-73 ◽  
pp. 613-616
Author(s):  
Regina Pinto de Carvalho ◽  
G.C. Silva ◽  
M. Sylvia S. Dantas ◽  
I.F. Vasconcelos ◽  
Virgínia S.T. Ciminelli
Keyword(s):  
Physical State ◽  
Unique Feature ◽  
Metal Accumulation ◽  
X Rays ◽  
Absorption Probability ◽  
X Ray ◽  
Analytical Technique ◽  
Absorption Phenomenon ◽  
Almost All ◽  
X Ray Absorption

X-Rays Absorption Fine Structure Spectroscopy (XAFS) is an analytical technique that can be used as a probe to characterize almost all elements, even if they appear in diluted or non-crystalline systems. This is due to the fact that the absorption probability of X-rays has a unique feature for each element, and is modulated by the chemical and physical state of that element, as well as by its neighborhood. This paper presents a brief description of the X-rays absorption phenomenon and the analytical technique involving this phenomenon, as well as the application of XAFS in biosorption studies. For more details on XAFS theory, refer to [1].

Pion transfer processes of pionic atoms in the gas mixtures containing hydrogen at various pressures

2001 ◽  
Vol 89 (11-12) ◽  
Author(s):  
Atsushi Shinohara ◽  
T. Miura ◽  
Akihiko Yokoyama ◽  
K. Takamiya ◽  
T. Kaneko ◽  
...  
Keyword(s):  
Gas Mixtures ◽  
X Rays ◽  
Capture Process ◽  
Transfer Processes ◽  
Pionic Atoms ◽  
Pion Capture

The pion capture process in gas mixtures containing hydrogen was studied by measuring pionic X rays and π

scholarly journals Analyse Du Rebut Des Cliches Radiographiques Dans Le Service De Radiologie Et Imagerie Médicale Du Chu Campus De Lomé Au Togo

2017 ◽  
Vol 13 (33) ◽  
pp. 244
Author(s):  
P. Gbande ◽  
L. Sonhaye ◽  
K. Adambounou ◽  
K. Lambon ◽  
B. N’timon ◽  
...  
Keyword(s):  
Medical Imaging ◽  
Prospective Study ◽  
Lower Limb ◽  
University Hospital ◽  
X Rays ◽  
Financial Loss ◽  
X Ray ◽  
Chest X Ray ◽  
Almost All

Purpose: To analyze the waste factors of rejected X-rays films. Methodology: Descriptive and analytical prospective study from 1 January to 30 June 2017 carried out in the department of radiology and medical imaging of the Campus University Hospital of Lomé in Togo. Results: 4912 patients had received 5630 radiographic incidences, including 3288 (58.4%) on the analogy and 2342 (41.5%) on the digital. The reject rate was 12.5%. The vast majority of the X-rays films, 682 (96.9%) were rejected by the radiographers themselves just after development. The resumption frequency ranged from one repeat (550 X-rays films, or 78%) to 4 repeats (8 X-rays films, or 1%). Almost all of the rejected films, 702 (99.7%) came from the analogical room. Chest X-ray was the incidence with more rejection in 33.9% followed by pelvic and lower limb incidences in 21% of cases. More than 2/3 of the rejected films, 473 (67.2%), came from the students' act. The causes of the rejection were mainly centering (25.5%), underexposure (20.17%) and overexposure (12.93). The financial loss caused by the scrap of X-rays films amounted to about 418800F CFA or 638.5 €. Conclusion: Strengthening communication between radiographers and radiologists is necessary to avoid unnecessary repeats of patient’s radiographs.

scholarly journals Hydrogen Effects on the Burst Properties of Type 304L Stainless Steel Flawed Vessels

2008 ◽  
Author(s):  
Michael J. Morgan ◽  
Monica C. Hall ◽  
Poh-Sang Lam ◽  
W. Dean Thompson
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Element Model ◽  
Burst Pressure ◽  
304L Stainless Steel ◽  
Helium Gas ◽  
Lower Volume ◽  
Hydrogen Deuterium ◽  
Deuterium Gas

The effects of hydrogen and burst media on the burst properties of Type 304L stainless steel vessels were investigated. The purpose of the study was to compare the burst properties of hydrogen-charged stainless steel vessels burst with different media: water, helium gas, and deuterium gas. A second purpose was to provide data to improve an existing finite-element model for predicting burst behavior. Burst tests were conducted on hydrogen-charged and uncharged axially-flawed cylindrical vessels. The results indicate that samples burst pneumatically had lower volume ductility than those tested hydraulically. For pneumatic burst tests, samples burst with deuterium gas had slightly lower ductility than helium gas tests. For uncharged samples, burst pressure was not affected by burst media. For samples pre-charged with hydrogen, deuterium burst pressures were about 80% of the hydraulic or helium burst pressures. Hydrogen-charged samples had lower volume ductility and slightly higher burst pressures than uncharged samples. The results of the tests were used to verify and improve a previously developed predictive finite-element model. The existing finite-element model can qualitatively predict the expected changes in burst properties with hydrogen or tritium service, but a better material property database is required for quantitative predictions.

scholarly journals Peering into buried interfaces with X-rays and electrons to unveil MgCO3 formation during CO2 capture in molten salt-promoted MgO

2021 ◽  
Vol 118 (26) ◽  
pp. e2103971118
Author(s):  
Alexander H. Bork ◽  
Margarita Rekhtina ◽  
Elena Willinger ◽  
Pedro Castro-Fernández ◽  
Jakub Drnec ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Alkali Metal ◽  
Growth Mechanism ◽  
Lattice Mismatch ◽  
Model System ◽  
Metal Salts ◽  
X Rays ◽  
Alkali Metal Salts ◽  
Capture Process ◽  
X Ray

The addition of molten alkali metal salts drastically accelerates the kinetics of CO2 capture by MgO through the formation of MgCO3. However, the growth mechanism, the nature of MgCO3 formation, and the exact role of the molten alkali metal salts on the CO2 capture process remain elusive, holding back the development of more-effective MgO-based CO2 sorbents. Here, we unveil the growth mechanism of MgCO3 under practically relevant conditions using a well-defined, yet representative, model system that is a MgO(100) single crystal coated with NaNO3. The model system is interrogated by in situ X-ray reflectometry coupled with grazing incidence X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. When bare MgO(100) is exposed to a flow of CO2, a noncrystalline surface carbonate layer of ca. 7-Å thickness forms. In contrast, when MgO(100) is coated with NaNO3, MgCO3 crystals nucleate and grow. These crystals have a preferential orientation with respect to the MgO(100) substrate, and form at the interface between MgO(100) and the molten NaNO3. MgCO3 grows epitaxially with respect to MgO(100), and the lattice mismatch between MgCO3 and MgO is relaxed through lattice misfit dislocations. Pyramid-shaped pits on the surface of MgO, in proximity to and below the MgCO3 crystals, point to the etching of surface MgO, providing dissolved [Mg2+…O2–] ionic pairs for MgCO3 growth. Our studies highlight the importance of combining X-rays and electron microscopy techniques to provide atomic to micrometer scale insight into the changes occurring at complex interfaces under reactive conditions.

scholarly journals Studies of THGEM-based detector at low-pressure Hydrogen/Deuterium, for AT-TPC applications

2015 ◽  
Vol 10 (09) ◽  
pp. P09020-P09020 ◽  
Author(s):  
Marco Cortesi ◽  
J. Yurkon ◽  
W. Mittig ◽  
D. Bazin ◽  
S. Beceiro-Novo ◽  
...  
Keyword(s):  
Low Pressure ◽  
Hydrogen Deuterium ◽  
Pressure Hydrogen

scholarly journals ROENTGEN RAY INTOXICATION

1922 ◽  
Vol 35 (2) ◽  
pp. 187-202 ◽  
Author(s):  
S. L. Warren ◽  
G. H. Whipple
Keyword(s):  
Small Intestine ◽  
Clinical Evidence ◽  
Clinical Work ◽  
X Rays ◽  
Fatal Intoxication ◽  
Unit Dose ◽  
Slight Rise ◽  
Almost All ◽  
Proper Consideration ◽  
Urinary Nitrogen

Roentgen radiation of the thorax (abdomen shielded) in dogs, even with large doses (up to 512 milliampere minutes), gives no clinical evidence of intoxication. There may be a transient leucopenia and a slight rise in urinary nitrogen. Roentgen radiation of the abdomen (thorax shielded) in dogs, with a dose of 350 milliampere minutes, will almost certainly cause a fatal intoxication. Smaller doses may be survived but usually with signs of gastrointestinal intoxication. This lethal intoxication due to abdominal radiation presents a remarkably uniform clinical and anatomical picture. There is a latent period of 24 to 36 hours, during which the dog is perfectly normal clinically. The 2nd day usually shows the beginning of diarrhea and perhaps some vomitus. The 3rd and 4th days show progressive intoxication with increasing vomiting and bloody diarrhea until the dog becomes stuporous. Death is almost always on the 4th day. Anatomically the only lesions of significance are to be found in the small intestine. The epithelium of the crypts and villi shows more or less complete necrosis, and this condition may involve almost all of the small intestine. The epithelium may vanish completely except for a few cells here and there which have escaped and are often found in mitosis, probably an effort at repair and regeneration. We are forced to the conclusion that this remarkable injury of the epithelium of the small intestine is responsible for the various abnormal reactions and final lethal intoxication which follow a unit dose of Roentgen radiation over the abdomen of a normal dog. This sensitiveness of the intestinal epithelium to x-rays is not appreciated and should be given proper consideration in clinical work.

scholarly journals High-resolution epitope mapping by HX MS reveals the pathogenic mechanism and a possible therapy for autoimmune TTP syndrome

2015 ◽  
Vol 112 (31) ◽  
pp. 9620-9625 ◽  
Author(s):  
Veronica C. Casina ◽  
Wenbing Hu ◽  
Jian-Hua Mao ◽  
Rui-Nan Lu ◽  
Hayley A. Hanby ◽  
...  
Keyword(s):  
Whole Body ◽  
Single Chain ◽  
Variable Regions ◽  
Exchange Mass Spectrometry ◽  
Change Effect ◽  
Polyclonal Igg ◽  
Hydrogen Deuterium ◽  
A Disintegrin And Metalloproteinase ◽  
Almost All ◽  
Von Willebrand

Acquired thrombotic thrombocytopenic purpura (TTP), a thrombotic disorder that is fatal in almost all cases if not treated promptly, is primarily caused by IgG-type autoantibodies that inhibit the ability of the ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) metalloprotease to cleave von Willebrand factor (VWF). Because the mechanism of autoantibody-mediated inhibition of ADAMTS13 activity is not known, the only effective therapy so far is repeated whole-body plasma exchange. We used hydrogen–deuterium exchange mass spectrometry (HX MS) to determine the ADAMTS13 binding epitope for three representative human monoclonal autoantibodies, isolated from TTP patients by phage display as tethered single-chain fragments of the variable regions (scFvs). All three scFvs bind the same conformationally discontinuous epitopic region on five small solvent-exposed loops in the spacer domain of ADAMTS13. The same epitopic region is also bound by most polyclonal IgG autoantibodies in 23 TTP patients that we tested. The ability of ADAMTS13 to proteolyze VWF is impaired by the binding of autoantibodies at the epitopic loops in the spacer domain, by the deletion of individual epitopic loops, and by some local mutations. Structural considerations and HX MS results rule out any disruptive structure change effect in the distant ADAMTS13 metalloprotease domain. Instead, it appears that the same ADAMTS13 loop segments that bind the autoantibodies are also responsible for correct binding to the VWF substrate. If so, the autoantibodies must prevent VWF proteolysis simply by physically blocking normal ADAMTS13 to VWF interaction. These results point to the mechanism for autoantibody action and an avenue for therapeutic intervention.

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